# When does the permanent magnet begin to accelerate?

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11 minutes ago, zetetic56 said:

I've been studying Physics on my own, and for the most part this has worked out fine, but every now and then I find myself stumbling into something that I think I understand but it turns out there is a whole bunch of knowledge behind what I'm looking at that I do not have.

I appreciate you trying to help me but in reading your response I think this may be one of those times I thought I was playing in the shallow end but I didn't realize I swam out too far.

I haven't studied field theory yet and I thought that without knowing a lot about fields I could understand my "electromagnet / permanent magnet " question by staying away from the details of fields and just sticking to the concept of " momentum ".

This makes no sense to me.  And I'm guessing it's because I don't understand fields and radiation and so on.

And so perhaps I need to just tuck away my little question for now and go back and finally get around to studying the basics of field theory.

Again, I appreciate you trying to help me, but I think I've swum out too far again on this one.

Thank you.

You're welcome. See you later. +1

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+1 to you too !  'till later : )

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We can divide this thought experiment into two parts.

a. What is mediating the electromagnetic force necessary for both magnets to start moving (attracting/repelling) towards or away from each other?

Answer: Photons will be responsible for this mediation.

b. When does this mediation begin?

Answer: The mediation begins as soon as the electromagnet is turned on because electromagnet is already within the magnetic field of the permanent magnet.

As soon as the mediation begins, which happens as soon as the electromagnet is turned on, the electromagnetic force necessary to affect mutual attraction or repulsion of the magnets is generated. So both magnets start to move towards or away from each other simultaneously.

Edited by Vikrant
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16 minutes ago, Vikrant said:

We can divide this thought experiment into two parts.

a. What is mediating the electromagnetic force necessary for both magnets to start moving (attracting/repelling) towards or away from each other?

Answer: Photons will be responsible for this mediation.

b. When does this mediation begin?

Answer: The mediation begins as soon as the electromagnet is turned on because electromagnet is already within the magnetic field of the permanent magnet.

As soon as the mediation begins, which happens as soon as the electromagnet is turned on, the electromagnetic force necessary to affect mutual attraction or repulsion of the magnets is generated. So both magnets start to move towards or away from each other simultaneously.

Imagine that the electromagnet was here on Earth while the permanent magnet was on a planet in Alpha Centauri. If your answer were correct, this arrangement would allow for an instantaneous, faster than light communication between the Earth and the planet in Alpha Centauri. We know that this is impossible, that no signal can travel faster than light. Thus, they would not start moving simultaneously, as per your suggestion.

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